Many computer programming languages and applications utilize object-oriented structures to model real world information. Object-oriented languages and applications access and store data in the form of entities such as objects and attributes. For example, many conventional applications used for querying and maintaining directory information systems are modeled using aspects of object-oriented techniques and entities. Directory information systems provide a framework for the storage and retrieval of information that are used to identify and locate the details of individuals and organizations, such as telephone numbers, postal addresses, and email addresses.
One common type of object-oriented based directory systems is a directory based on the Lightweight Directory Access Protocol (“LDAP”). LDAP is a directory protocol that was developed at the University of Michigan, originally as a front end to access directory systems organized under the X.500 standard for open electronic directories. Standalone LDAP server implementations are now commonly available to store and maintain directory information.
LDAP Knowledge References, also called knowledge referral entries or referrals, are Directory entries that can be used to contain remote Directory Server and Directory Information Tree (DIT) information. For example, since it is possible to partition the Directory content. (DIT and entries) among multiple Directory servers, each Directory server in the partition group maintains a referral entry that points to the other Directory servers for relevant partitions of the DIT.
When the LDAP Directory Server services an LDAP Search request from a client, the knowledge referral entries that are relevant to the search scope can be returned as part of the search result set. There are two main portions of the LDAP Search request that determine the search result set, the base and the filter. The base of the search specifies the root of the hierarchical DIT for this search. The filter specifies the Attribute Value Assertions, which, if satisfied, places the entry in the result set.
For example, in a search for an individual named John Doe in the payroll organizational unit of Acme company, the base may look like base=“ou=payroll,o=acme.com” and the filter may look like filter=“uid=jdoe”. There is a need for the Directory Server to return not only the entries that have a user ID (UID) value of ‘jdoe’ but also the referral entries that are present in the DIT under the specified base.
Currently there exists no mechanism to represent and obtain both directory entry data and knowledge referral data from a relational database system. There is a need for a mechanism to represent and obtain both LDAP entry and LDAP referral information from a relational database system.